GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
36 Keys, Doors, and Windows
To adjust each mirror:1. Press
jor|to select the driver or
passenger side mirror. The indicator light
will illuminate.
2. Press the arrows on the control pad to move the mirror in the desired direction.
3. Adjust each outside mirror so that a little of the vehicle and the area behind it can
be seen.
4. Press
jor|again to deselect the
mirror.
Turn Signal Indicator
If equipped, the mirror has turn signal
indicator lights, which flash in the direction
of the turn or lane change.
Task Lighting
If equipped, task lighting projects light from
the outside mirrors to the sides of the
vehicle. See Task Lighting 0148. Puddle Lamps
If equipped, puddle lamps project light from
the bottom of the mirror to the area of
ground below the driver and passenger
doors. See
Entry Lighting 0151 and
Exit Lighting 0151.
Memory Mirrors
The vehicle may have memory mirrors. See
Memory Seats 051.
Lane Change Alert (LCA)
The vehicle may have LCA. See Lane Change
Alert (LCA) 0268.
Folding Mirrors
Manual Folding Mirrors
If equipped, push the mirror toward the
vehicle to fold. Push the mirror outward to
return to its original position.
Manually fold the mirrors inward to prevent
damage when going through an automatic
car wash.
Power Folding Mirrors
If equipped, pressgto power fold the
mirrors. Press again to unfold.
Resetting the Power Folding Mirrors
Reset the power folding mirrors if:
.The mirrors are accidentally obstructed
while folding.
.The mirrors are accidentally manually
folded/unfolded.
.The mirrors will not stay in the unfolded
position.
.The mirrors vibrate at normal driving
speeds.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 47
Head Restraints{
Warning
With head restraints that are not
installed and adjusted properly, there is a
greater chance that occupants will suffer
a neck/spinal injury in a crash. Do not
drive until the head restraints for all
occupants are installed and adjusted
properly.
Front Seats
The vehicle's front seats have adjustable
head restraints in the outboard seating
positions.
Adjust the head restraint so that the top of
the restraint is at the same height as the
top of the occupant's head. This position
reduces the chance of a neck injury in a
crash.
To raise or lower the head restraint, press
the button on the side of the head restraint
and pull up or push the head restraint down
and release the button.
Pull and push on the head restraint after the
button is released to make sure that it is
locked in place.
The front seat outboard head restraints are
not removable.
Rear Head Restraints
The vehicle’s rear seat has head restraints in
the outboard seating positions that cannot
be adjusted.
The head restraint can be folded forward to
allow for better visibility when the rear seat
is unoccupied. To fold the head restraint,
press the button on the side of the head
restraint.
When an occupant is in the seat, always
return the head restraint to the upright
position until it locks into place. Push and
pull on the head restraint to make sure that
it is locked.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
48 Seats and Restraints
If you are installing a child restraint in the
rear seat, seeLower Anchors and Tethers for
Children (LATCH System) 081.
Center Headrest
The vehicle’s rear seat may be equipped
with a headrest in the center seating
position that cannot be adjusted.
If you are installing a child restraint in the
rear seat, see Lower Anchors and Tethers for
Children (LATCH System) 081.
Front Seats
Seat Adjustment
{Warning
You can lose control of the vehicle if you
try to adjust a driver seat while the
vehicle is moving. Adjust the driver seat
only when the vehicle is not moving.
To adjust a manual seat:
1. Pull the handle at the front of the seat.
2. Slide the seat to the desired position and release the handle.
3. Try to move the seat back and forth to be sure it is locked in place.
To adjust the seatback, see Reclining
Seatbacks 049.
To adjust the lumbar support, if equipped,
see Lumbar Adjustment 050.
Center Seat
If equipped, the center front seatback
doubles as an armrest and cupholder/
storage area for the driver and passenger
when the center front seat is not used.
Pull the strap on the side of the center
seatback to fold the center seatback. Do not
use the center seatback as a seating position
when the seatback is folded down.
To raise the seatback, push the seatback
rearward until it locks in the upright
position. Push and pull on the seatback to
make sure it is locked.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
56 Seats and Restraints
The feature can be turned on or off. Select
Settings > Vehicle > Rear Seat Reminder >
ON or OFF.
Folding the Rear Seat Cushion
Either side of the rear seat cushion can be
folded up for added cargo space.
Caution
Folding a rear seat with the seat belts
still fastened may cause damage to the
seat or the seat belts. Always unbuckle
the seat belts and return them to their
normal stowed position before folding a
rear seat.
Make sure that nothing is on the seat
cushion.
To fold the seat, slowly pull the seat
cushion up.
To return the seat to the normal seating
position, slowly pull the seat cushion down.
{Warning
A seat belt that is improperly routed, not
properly attached, or twisted will not
provide the protection needed in a crash.
The person wearing the belt could be
seriously injured. After restoring the seat
to the normal seating position, always
check to be sure that the seat belts are
properly routed and attached, and are
not twisted.
Heated Rear Seats
{Warning
If you cannot feel temperature change or
pain to the skin, the seat heater may
cause burns. See the Warning under
Heated and Ventilated Front Seats 054.
If available, the buttons are on the rear of
the center console. To operate, the engine
must be running.
Press
MorLto heat the left or right
outboard seat cushion. An indicator on the
climate control display appears when this
feature is on.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
60 Seats and Restraints
Never wear the shoulder belt under both
arms or behind your back.
Always use the correct buckle for your
seating position.
Never route the lap or shoulder belt over an
armrest.
{Warning
The seat belt can be pinched if it is
routed under plastic trim on the seat,
such as trim around the rear seatback
folding handle or side airbag. In a crash,
pinched seat belts might not provide
adequate protection. Never allow seat
belts to be routed under plastic trim
pieces.
{Warning
You can be seriously injured or killed if
the shoulder belt is worn behind your
back, under your legs, or wrapped around
your neck. The shoulder belt can tighten
but cannot be loosened if it is locked. The
shoulder belt locks when it is pulled all
the way out of the retractor. It unlocks
when the shoulder belt is allowed to go
all the way back into the retractor, but it
cannot do this if it is wrapped around
you. You may have to cut the seat belt if
it is locked and tightened around you.
Lap-Shoulder Belt
All seating positions in the vehicle have a
lap-shoulder belt.
The following instructions explain how to
wear a lap-shoulder belt properly.1. Adjust the seat, if the seat is adjustable, so you can sit up straight. To see how,
see “Seats” in the Index.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
86 Seats and Restraints
According to accident statistics, children and
infants are safer when properly restrained in
a child restraint system or infant restraint
system secured in a rear seating position.
SeeWhere to Put the Restraint 080 for
additional information.
Securing a Child Restraint Designed for
the LATCH System
{Warning
A child could be seriously injured or killed
in a crash if the child restraint is not
properly attached to the vehicle using
either the LATCH anchors or the vehicle
seat belt. Follow the instructions that
came with the child restraint and the
instructions in this manual.
{Warning
Do not attach more than one child
restraint to a single anchor, except for
the center top tether anchors in the crew
cab models. Attaching more than one
child restraint to a single anchor could
cause the anchor or attachment to come
loose or even break during a crash.
(Continued)
Warning (Continued)
A child or others could be injured. To
reduce the risk of serious or fatal injuries
during a crash, attach only one child
restraint per anchor.
{Warning
Children can be seriously injured or
strangled if a shoulder belt is wrapped
around their neck. The shoulder belt can
tighten but cannot be loosened if it is
locked. The shoulder belt locks when it is
pulled all the way out of the retractor.
It unlocks when the shoulder belt is
allowed to go all the way back into the
retractor, but it cannot do this if it is
wrapped around a child’s neck. If the
shoulder belt is locked and tightened
around a child’s neck, the only way to
loosen the belt is to cut it.
Buckle any unused seat belts behind the
child restraint so children cannot reach
them. Pull the shoulder belt all the way
out of the retractor to set the lock, and(Continued)
Warning (Continued)
tighten the belt behind the child restraint
after the child restraint has been
installed.
Caution
Do not let the LATCH attachments rub
against the vehicle’s seat belts. This may
damage these parts. If necessary, move
buckled seat belts to avoid rubbing the
LATCH attachments.
Do not fold the rear seat cushion when
the seat is occupied. Do not fold the
empty rear seat with a seat belt buckled.
This could damage the seat belt or the
seat. Unbuckle and return the seat belt to
its stowed position, before folding
the seat.
If you need to secure more than one child
restraint in the rear seat, see Where to Put
the Restraint 080.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 213
Using heavier suspension components
to get added durability might not
change the weight ratings. Ask your
dealer to help load the vehicle the
right way.
{Warning
Things you put inside the vehicle can
strike and injure people in a sudden
stop or turn, or in a crash.
.Put things in the cargo area of the
vehicle. Try to spread the weight
evenly.
.Never stack heavier things, like
suitcases, inside the vehicle so
that some of them are above the
tops of the seats.
.Do not leave an unsecured child
restraint in the vehicle.
.When you carry something inside
the vehicle, secure it whenever
you can.
.Do not leave a seat folded down
unless you need to. There is also important loading
information for off-road driving in this
manual. See
“Loading the Vehicle for
Off-Road Driving“ underOff-Road
Driving 0203.
Two-Tiered Loading
Depending on the model of the pickup,
an upper load platform can be created
by positioning three or four 5 cm (2 in)
by 15 cm (6 in) wooden planks across
the width of the pickup box. The planks
must be inserted in the pickup box
depressions.
When using this upper load platform,
be sure the load is securely tied down
to prevent it from shifting. The load's
center of gravity should be positioned
in a zone over the rear axle. The zone is
located in the area between the front
of each wheel well and the rear of each
wheel well. The center of gravity height
must not extend above the top of the
pickup box flareboard. Any load that extends beyond the
vehicle's taillamp area must be properly
marked according to local laws and
regulations.
Remember not to exceed the Gross Axle
Weight Rating (GAWR) of the front or
rear axle.
Add-On Equipment
When carrying removable items, a limit
on how many people carried inside the
vehicle may be necessary. Be sure to
weigh the vehicle before buying and
installing the new equipment.
Caution
Overloading the vehicle may cause
damage. Repairs would not be covered by
the vehicle warranty. Do not overload the
vehicle.
Remember not to exceed the Gross Axle
Weight Rating (GAWR) of the front or
rear axle.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Index 429
Engine (cont'd)Running While Parked . . . . . . . . . . . . . . . . . 223
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Equipment, Towing . . . . . . . . . . . . . . . . . . . . . . 284
Event Data Recorders . . . . . . . . . . . . . . . . . . . . .415
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Extended Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . .35
Extended Parking . . . . . . . . . . . . . . . . . . . . . . . . 222
Extender, Seat Belt . . . . . . . . . . . . . . . . . . . . . . . 63
Exterior Cargo Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Lamp Controls . . . . . . . . . . . . . . . . . . . . . . . . . 143
Lamps Off Reminder . . . . . . . . . . . . . . . . . . . 145
Lighting Battery Saver . . . . . . . . . . . . . . . . . 152
F
Fan
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Filter Engine Air Cleaner . . . . . . . . . . . . . . . . . . . . . 318
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
Flashers, Hazard Warning . . . . . . . . . . . . . . . . 146
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Floor Console
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391 Fluid
Automatic Transmission . . . . . . . . . . . . . . . . 317
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
Power Steering . . . . . . . . . . . . . . . . . . . . . . . . 323
Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Fog Lamp Light Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . 228, 329
Four-Wheel-Drive Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
Heated and Ventilated Seats . . . . . . . . . . . . 54
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
E85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Economy, Driving for Better . . . . . . . . . . . 199
Filling a Portable Fuel Container . . . . . . . 276
Filling the Tank . . . . . . . . . . . . . . . . . . . . 273, 275
Foreign Countries . . . . . . . . . . . . . . . . . . . . . . 272
Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Low Fuel Warning Light . . . . . . . . . . . . . . . 129 Fuel (cont'd)
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . 272
Recommended . . . . . . . . . . . . . . . . . . . . . . . . . 272
Top Tier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Full-Size Spare Tire . . . . . . . . . . . . . . . . . . . . . . . 375
Fuses Engine Compartment Fuse Block . . . . . . . 337
Fuses and Circuit Breakers . . . . . . . . . . . . . 337
Instrument Panel Fuse Block . . . . . . 341, 342
G
Garage Door Opener . . . . . . . . . . . . . . . . . . . . . 140
Programming . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Gauges Engine Coolant Temperature . . . . . . . . . . . . 118
Engine Oil Pressure . . . . . . . . . . . . . . . . . . . . . 117
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Transmission Temperature . . . . . . . . . . . . . . 119
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Voltmeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Warning Lights and Indicators . . . . . . . . . . 111
General Information
Service and Maintenance . . . . . . . . . . . . . . 393
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276